The present invention relates to digital to analog converters comprising a mixer.
In some applications, signals are processed digitally, converted to analog signals and then mixed with a local oscillator signal to obtain a signal with a desired frequency. An example for such an application are wireless transmitters, where signals are processed digitally at a so-called baseband frequency, converted to an analog signal via a digital to analog converter (DAC) and mixed with a radio frequency signal to obtain a radio frequency transmit signal, which is then transmitted via an antenna.
With some structures used for this purpose, so-called local oscillator (LO) leakage occurs, which is the power of the frequency of the local oscillator signal when a signal output by the digital to analog converter is at zero, or in other words the digital signal input to the digital to analog converter indicates a zero, in comparison to the signal when the output of the to analog converter assumes its maximum value.